fix to work lienar/cosine lr scheduler closes #1602 ref #1393

Author: kohya-ss

library/train_util.py

@@ -4707,6 +4707,15 @@ def wrap_check_needless_num_warmup_steps(return_vals):
             **lr_scheduler_kwargs,
         )
 
+    # these schedulers do not require `num_decay_steps`
+    if name == SchedulerType.LINEAR or name == SchedulerType.COSINE:
+        return schedule_func(
+            optimizer,
+            num_warmup_steps=num_warmup_steps,
+            num_training_steps=num_training_steps,
+            **lr_scheduler_kwargs,
+        )
+
     # All other schedulers require `num_decay_steps`
     if num_decay_steps is None:
         raise ValueError(f"{name} requires `num_decay_steps`, please provide that argument.")
@@ -5837,14 +5846,9 @@ def sample_image_inference(
         wandb_tracker = accelerator.get_tracker("wandb")
 
         import wandb
+
         # not to commit images to avoid inconsistency between training and logging steps
-        wandb_tracker.log(
-            {f"sample_{i}": wandb.Image(
-                image,
-                caption=prompt # positive prompt as a caption
-            )}, 
-            commit=False
-        )
+        wandb_tracker.log({f"sample_{i}": wandb.Image(image, caption=prompt)}, commit=False)  # positive prompt as a caption
 
 
 # endregion